Improvement in water-tube steam-boilers



M; mmm W. J. MUNCASTER.

WATER-TUBE STEAM-Boum. v N0,174,55z; Patented March 7,1876.

N.PETERS. PHOTU-LXTHDGRAPHER. WASHINGTON. D C.

grates, to the front tube-sheet.

UNITED STATES PATENT. Qrron.

A M EnwIN Maxam AND'WALTER J. Mono/ASTER, or OUMBERLAND, MD.

IMPROVEMENT IN WATER-TUBE s'TEAMfBoILERs;

Specitication forming part of Letters Patent No. 174,552, dated March 7,1876; application filed January 20, 1876.

To all whomit may concern:

Be it known that we, MERWIN MGKAIG and WALTER J. MUNCASTER, oit'Cumberland,

in the county of Allegheny and State of Maryland, have invented certainnew and valuable Improvements in Steam Boilers, intended moreparticularly for canal-boats and steamtugs, but applicable to land orany purpose or place where economy of fuel and space is desired, ofwhich the following` is a specitication Figure l is a longitudinalsection, and Fig. 2 is a transverse section, ot' my boiler. Fig. 3 is atransverse section of the tubes, showing' the bridge-wall blocks.

This invention relates to a boiler of the water-tube type, and itconsists, first, of watertubes inelining downward from their front ends,at an angle of about twenty degrees, to a point j ust in rear of thebridge-wall,whence to the rear ends they are horizontal or nearly so,whereby, at their forward and hottest ends, steam and hot water have afree escape upward 5 and the tubes are, at all points, sub,- stantiallytransverse or at right angles to the draft or current of hot products ofcombustion, and are all equally exposed to the heat thereof; second, ina bridge-wall, constructedof blocks slipped onto the pipes, andoverlapping each other, whereby the pipes are not crmped in theirexpansion and contraction; third, in external form, a box, A, withsemi-cylindrical top, provided with a steam-dome, a.

The interior chamber, composing the furnace and tube-box B, correspondssomewhat to the outside shell in shape, with a tlat elliptical top,reaching within tive inches or six inches ofthe water-line, and thevertical Walls slightly inclined to provide a gradual increase ofwater-space.' The front and back heads b ot this chamber are drilled toreceive and support the tubes c, which stretch across through theinterior in vertically-staggered rows, which staggering makes thetube-surface more effective. The axes of these tubes are horizontal orslightly inclined from back tube-sheet to a point in line lwithbridge-wall D, then deect upward at an angle of about twenty degrees,passing through the b1 idge -wall, over the The object of this is to'cause rapid circulation, induced by the tubes being inclined. The bendcaused thereby provides for expansion and contraction, which in all straighttubes cause an enormous strain on the tube-sheets. The plates ofoutside shell are also provided with circular openingsE, correspondingwith the center line of tubes, for the purpose of cleaning andreplacing, and are closed with suitable plates and nuts, or the holestapped and bungs screwed in. The lower portion of the front is piercedwith an opening of proper size for furnace-door F. At the rear of thefurnacechamber, and above the tubes, there is an opening, G, of propersize, for the purpose of being able to examine and clean the upper spaceabove the tubes;l also, to replace a crown-bolt without removingthetubes. This opening communicates with the smoke-stack H, and isclosed by a suitable damper, I, which will be found advantageous instarting the fire, because opening this damper will allow the productsof combustion to pass directly into the stack, which may be formed onthe back of the boiler; when the tire is well started, this damper isclosed, causing the products of combustion to pass downward through thetubes to the base of the stack. At the back end of the furnace-chamber,and under the tubes, is placed a mud-drum, J, attached to the leg of theboiler, in which the feed-Water is received. When in position, thisboiler rests upon a casting, K, forming the ash-pit and smoke-due, whichalso furnishes/ the support for the grate-bars and bridge-wall D anopening, L, is formed in the side of same for cleaning. The extension ofthe bridge-wall upward among the tubes is formed of blocks d slipped oneach tube, and projecting far enough to lap the block on the next tubebelow, but not to come in contact with the tube, which allows each tubeto expand.

and contract independent of the others. Below the tubes the bridge-wallD is formed, preferably ofire-brick, supported by a plate of iron at theback.

From the above description, it will be per ceived that the tubes restin, and are wholly supported by, their coupling to the tube-sheets b andb, and that their change of direction at or near the bridge-wall` placestheiru midway portions at a distance from a right line, joining theirends; therefore, any expansion-orf contraction lengthwise will be`partly or wholly: counterbalanced by an increased or diminisheddeflection of said tubes, and thus the tubesheet connections will besubjected "to less strain than would be the case if said tubeswerestraight.v This'e'ectis facilitated bythe structure of thebridge-wall, which permits the utmost freedom of motion there.

Having described'our invention, what We claim as new is- 1. Thewater-tubes C C, connected at their rear ends to the rear tnbe-sheetb'," and 'pass'ing thence forward, horizontally or nearly so,to a pointjust in rear of the bridge-Wall', then, bending upward at an angle oftwenty degrees or' thereabouts,` they pass through thebridgei wall andover the grate to the front tubes'heet b', therebybeing `at allf pointstransverse or at?l as' set forth.

right angles tothe draft, and with a free nii ward discharge atthe hotend, substantially 2. A bridge-wan formed of blocks d a, slipped onto,and combined with, the Water-tubes, s0

as to lap one another and `permit freedom of -motion-in-s`aid tubes in 1expanding and .'contracting, as set forth.

3. In combination, the within -described V'tubes'c, bridge-wall d,furnace-chamber B,

surrounded by an outside shell, with steamdome and flue H, anddirectdamper G, ar-

* ranged? sbstantiallyas' described.

MERWIN MKAIG. W. J. MUNCASTER.

Witnesses 4WM. L. ,MoRGAN, H. IW-ALLGERD.

